This invention is related to an automatic flow rate controller which employs a pressure differential impeller to automatically maintain a constant flow rate to a controlled part, despite variations in fluid pressure, and more particularly to such a controller having a minimal number of components.
Typical controllers include an impeller, a retaining washer, a lock nut, a screw, an end cap, a spring, a valve sleeve, and a valve tube. A fixed but adjustable orifice creates the differential pressure across the impeller to maintain a constant flow output. The impeller reciprocates with a valve sleeve driven by a force balance between a fluid pressure differential across the impeller and a spring force. The impeller moves axially with the valve sleeve to open or close valve ports in the valve tube. In a typical controller, the impeller and the valve sleeve are separate components.